What Custody Tools Know About You — And Why It Matters
Every tool that touches your Bitcoin knows something about how it is held. Most people don't realize how many services carry information about their custody setup.
This memo is descriptive. It does not recommend or compare specific products.
Your custody system is bigger than your wallet
Most people think their Bitcoin custody system is their wallet. It isn't. Your custody system is every tool, service, device, and person that has ever touched information about how your Bitcoin is held.
The exchange where you bought it knows your identity and your transaction history. The hardware wallet manufacturer knows your shipping address. The collaborative custody service knows your key distribution. The documentation platform knows your wallet map, your heirs, and your recovery instructions. The password manager may hold credentials that protect your keys.
Each one carries a different amount of information about your custody arrangement. Each one creates a different type of exposure if it is breached, subpoenaed, or disappears. Understanding what each tool knows — and what happens to that information under stress — is part of understanding your custody system.
Exposure profiles at a glance
The following matrix describes the structural exposure profile of each category of tool that commonly touches a Bitcoin custody system. It does not evaluate specific products.
| Tool category | Knows your identity |
Knows your custody structure |
Stores data about you |
Creates ongoing dependency |
Breach exposes custody details |
Works if provider disappears |
|---|---|---|---|---|---|---|
| Exchange | Yes | Yes | Yes | Yes | Yes | No |
| Hardware wallet manufacturer | Partial | No | Partial | No | Partial | Yes |
| Software wallet | No | No | No | No | No | Yes |
| Collaborative custody service | Yes | Yes | Yes | Yes | Yes | Partial |
| Multisig coordinator | Varies | Partial | Varies | No | Varies | Yes |
| Inheritance & documentation platform | Yes | Yes | Yes | Yes | Yes | Partial |
| Password manager | Yes | Often | Yes | Yes | Yes | Partial |
| Estate attorney or fiduciary | Yes | Partial | Yes | No | Partial | Yes |
| CustodyStress | No | No | No | No | No | Yes |
This matrix describes structural properties of tool categories, not individual products. Specific implementations may vary.
What each category knows
Exchanges
An exchange holds your Bitcoin on your behalf. It knows your legal identity, your balance, your transaction history, and your banking information. Governments can subpoena this data. If the exchange is breached, your identity is linked to your holdings. If the exchange disappears or freezes your account, your Bitcoin is inaccessible until the situation is resolved — if it is resolved at all.
Hardware wallet manufacturers
A hardware wallet manufacturer does not hold your keys. But if you purchased the device online, the manufacturer may know your shipping address, your email, and your phone number. This information tells an attacker that you own Bitcoin and where you live. The 2020 Ledger data breach exposed the personal information of approximately 270,000 customers, leading to targeted phishing and physical threat campaigns. The device itself works without the manufacturer, but the purchase record creates exposure that persists indefinitely.
Software wallets
Most software wallets run locally on your device and do not require an account or identity. They generally do not transmit custody information to a server. Some wallets connect to external servers to check balances or broadcast transactions, which can expose your IP address and your Bitcoin addresses depending on the configuration. Open-source wallets that connect to your own node minimize this exposure. If the software is discontinued, your keys still work with any compatible wallet.
Collaborative custody services
A collaborative custody service holds one or more keys in your multisig arrangement. It knows your identity, your key distribution, your co-signers, and the structure of your custody setup. It requires KYC and an ongoing account. It may offer inheritance protocols that depend on the service remaining operational. If the service disappears, you may need to recover using only the keys you hold independently — which may or may not be enough to meet your signing threshold, depending on how the multisig was configured.
Multisig coordinators
A multisig coordinator helps you create and manage a multisig wallet without holding any of your keys. It knows the structure of your multisig — how many keys, what threshold, which devices — but the amount of personal information it collects varies by product. Some require no account. Others require an email or identity. If the coordinator disappears, your multisig still functions because the keys are held independently. The coordinator makes the setup easier but is not required to operate it.
Inheritance and documentation platforms
An inheritance or documentation platform records your custody arrangement: which wallets you have, where the backups are stored, who the heirs are, what the recovery steps are, and who should be contacted. It does not hold your keys. But it holds a complete map of your custody system. That map is arguably more sensitive than any single key, because it tells anyone who accesses it exactly how to target every component of the setup. These platforms typically require an account, store data on their servers, and may offer liveness checks or dead man's switches that create an ongoing dependency on the platform remaining operational.
Password managers
A password manager is not a Bitcoin product, but many people use it as custody infrastructure without realizing it. If your hardware wallet PIN, your exchange password, your passphrase, or your multisig coordinator login is stored in a password manager, then the password manager is part of your custody system. If the master password is lost, the account is locked, or the provider changes their recovery process, access to credentials that protect your keys may be lost — even though the keys themselves still exist. A breach of the password manager can expose the credential layer that protects every other component of the custody system.
Estate attorneys and fiduciaries
An attorney or fiduciary who helps with estate planning may hold information about your custody arrangement in their files: which assets exist, how they are held, who the beneficiaries are. This information is protected by professional confidentiality but still exists as a physical or digital record in their office or document management system. It is subject to office breaches, employee access, and legal discovery. If the professional retires, changes firms, or dies, their files may be transferred, archived, or lost. The information they hold is typically partial — they know about your custody arrangement but usually do not hold the technical details needed to access it.
CustodyStress
CustodyStress evaluates how your custody system behaves under stress. It does not know who you are. It does not connect to your wallets. It does not store the information you provide. It processes your declared inputs, produces a reference artifact, and exits. If CustodyStress disappears, the artifact you printed or saved still functions. There is no account to breach, no data to subpoena, no dependency to maintain. CustodyStress is designed to observe the system from outside it without ever becoming part of it.
Why this matters
Most people evaluate custody tools based on what the tool does for them. That is reasonable. But every tool that touches your custody system also creates an exposure profile — a set of information that exists somewhere about how your Bitcoin is held, who you are, and how access works.
These exposure profiles accumulate. A person who uses an exchange, a hardware wallet, a collaborative custody service, a documentation platform, and a password manager may have a strong custody setup — but their custody information now exists in five separate systems, each with its own breach surface, subpoena exposure, and continuity risk.
Understanding what each tool knows is not about avoiding tools. It is about understanding what your full custody system actually looks like — not just the keys and the wallets, but every service and person that carries information about them.
This memo describes structural properties of tool categories commonly used in Bitcoin custody. It does not evaluate or recommend specific products.
Version 1.0 — Published March 2026.
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